采用MP2和CIS方法分别优化trans-[M2(CN)4(PH2CH2PH2)2][M=Pt(1),Pd(2)和Ni(3)]和trans-[M(cN)2(PH3)2][M=Pt(4),Pd(5)和Ni(6)]的基态和1.0[(dz^2)(pz)]激发态结构.CIS计算显示1的激发态Pt-Pt距离相对基态变短,而2和3的金属间距离却增长.TD-DFT方法合理地预测了1~6发射能,如:1在CH2Cl2溶液中分别拥有348和404nm的荧光和磷光发射,与实验的386和448nm相对应.在1~3的激发态中,d^8-d^8相互作用依次递减,相应的发射跃迁能增加;与单核配合物4~6相比,金属间相互作用使得双核Pt配合物的发射波长红移,而对双核Pd和Ni配合物影响很小.
The structures of trans-[M2(CN)4(PH2CH2PH2)2] [M=Pt (1), Pd (2) and Ni (3)] and trans- [M(CN)2(PH3)2] [M=Pt (4), Pd (5) and Ni (6)] in the ground and 1,3[ (dz2) (Pz)] excited states were optimized by the MP2 and CIS methods, respectively. The CIS calculations revealed that upon excitation the Pt-Pt distance of 1 shortens but those of 2 and 3 lengthened. Experimental emissions were well reproduced by the TD-DFT calculations. For example, the fluorescent/phosphorescent emissions of I were predicted to take place at 356/417 nm in the solid state and at 348/404 nm in the CH2Cl2 solution, agreeing with experimental 388/450 and 386/448 nm, respectively. It is shown that the metal-metal interaction decreases on going from 1 to 3 in their excited states, leading to the increase of the σ(pz)→σ(dz^2) emission energy along the series complexes. With respect to analogous mononuclear d8 complexes (4-6), the d^8-d^8 interaction results in a large red shift of emission wavelength for the binuclear Pt(Ⅱ) complex but slightly affects those of the binuclear Pd(Ⅱ) and Ni(Ⅱ) complexes.